Risk of second cancer from scattered radiation of intensity-modulated radiotherapies with lung cancer

Abstract

PurposeTo compare the risk of secondary cancer from scattered and leakage doses following intensity-modulated radiotherapy (IMRT), volumetric arc therapy (VMAT) and tomotherapy (TOMO) in patients with lung cancer.MethodsIMRT, VMAT and TOMO were planned for five lung cancer patients. Organ equivalent doses (OEDs) are estimated from the measured corresponding secondary doses during irradiation at various points 20 to 80 cm from the iso-center by using radio-photoluminescence glass dosimeter (RPLGD).ResultsThe secondary dose per Gy from IMRT, VMAT and TOMO for lung cancer, measured 20 to 80 cm from the iso-center, are 0.02~2.03, 0.03~1.35 and 0.04~0.46 cGy, respectively. The mean values of relative OED of secondary dose of VMAT and TOMO, which is normalized by IMRT, ranged between 88.63% and 41.59% revealing 88.63% and 41.59% for thyroid, 82.33% and 41.85% for pancreas, 77.97% and 49.41% for bowel, 73.42% and 72.55% for rectum, 74.16% and 81.51% for prostate. The secondary dose and OED from TOMO became similar to those from IMRT and VMAT as the distance from the field edge increased.ConclusionsOED based estimation suggests that the secondary cancer risk from TOMO is less than or comparable to the risks from conventional IMRT and VMAT.

Dosimetric study of volumetric arc modulation with RapidArc and intensity-modulated radiotherapy in patients with cervical cancer and comparison with 3-dimensional conformal technique for definitive radiotherapy in patients with cervical cancer

“…Thus, low doses to the whole body were increased, and secondary malignancy risk was increased even though this is controversial. 6,30,31 Our studies showed the same results as literature data for IMRT and VMAT comparison. OAR sparing was the same for both techniques.…”

Estimating second malignancy risk in intensity-modulated radiotherapy and volumetric-modulated arc therapy using a mechanistic radiobiological model in radiotherapy for carcinoma of left breast

“…Several studies suggest that increase in MU results in increased SCR, and these studies attributed it to increased head leakage and collimator scatter. [ 31 32 ]…”

Influence of Distinct Radiotherapy Techniques to Induce Second Cancer Risks in Left Breast Cancer

“…Second cancer risks for in-field organs were more than for organs outside of treatment field with an exception for ITF and VMAT plan [16]. Optimization and conformation to treated volume consequence reduce in relative OED in all three relationships dose-response.…”

“…Where TOMO, is less than or compatible with the secondary of the dose and OED from conventional IMRT and VMAT but TOMO is similar to IMRT and VMAT as increasing the distance from the field edge [16]. Organs near to the PTV have rising risk to stimulate second cancer [25].…”